Figure 4. Schematic of the electronic band structure variations.

(a) I–V characteristics of the LRS and HRS branch of the double barrier device in the reverse voltage regime of the Schottky contact (device area is normalized to 1 μm²). Solid lines are data fits according to Equation 1 to extract the Schottky barrier height ϕ_B. (b) Comparison between the Schottky contact resistance at the LRS and HRS branch and the tunnelling resistance. Inset: Shift of the diode forward current onset. (c) Schematic electronic band diagram of the double barrier structure for the LRS (red line) and HRS (blue line). During the transition from the HRS to LRS, moving oxygen ions cause an decrease of the interfacial potential V_I by a down shift of the interfacial band in Nb_xO_y (dashed line). Further, the effective barrier tunnel width d_eff and the apparent barrier heights ϕ_Al, and ϕ_Au of ,respectively, the Al electrode, and Au contact are decreased.